Heater



Nov. 26, 1946. H. J. DE: N. MccoLLuM 2,411,553

umm l-ned han 1. 194s 2 Sheets-Sheet. 2

Patented Nov. 26, 1946 'animes a usarsi; f Henry J. De N. McCollum, Chicago, lli.; Thelma McCollum, executrix of` said Henry J. De N.

deceased McCollum,

assignor to v Stewart- Warner Corporation, Chicago, Iii., a corporation of Virginia Application mmh 1, 194s, sensi No. 477,507

' 12 claim. (C1. 12s-111i)` My invention relates to heaters,A and more particularly to heaters .of the internal combustion type. y

An object of my invention is to provide an in ternal combustion type oi heater` wherein the combustion will be more uniform and thorough,

whereby the emciency oi' the heater is increased..

' Another object of my invention is to provide a heaterv having an improved arrangement of induction tubes for delivering a combustible mixture to the combustion chamber.

Another object of my invention is to provide a heater having improved means for supplying combustible mixture simultaneously to different parts of the combustion chamber.

lar passage I8, these gases give uptheir heat to Another object of my invention is to provide a heater having improved means for preheating the combustible mixturedelivered to the combustion chamber. 1 i

Another object of my invention is to provide a heater having a more even distribution of flame in the combustion chamber. Other objects and advantages will become apparent as the description proceeds. l

In the drawings:

Fig.l 1 is a partial longitudinal section through a heater embodying one form oi' my invention:

Fig. 2 is a transverse section taken 'on the line y2--2 or ris. 1:

the Ventilating air tubes 22. T-he cooled gases oi combustion are discharged to atmosphere from the righthand end oi' the passage I8, whereas the Ventilating air, having absorbed heat from the walls of the tubes 22, is delivered to the cabin of an airplane o r other space to be heated.4

The heater has an air inlet 24 which may be supplied'with air by a ram, blower or any other ysuitable means. Part of this air-flows around the combustion chamber I0 and enters the ventilating air tubes 22 to be heated by the hot products of combustion ilowing around these tubes. 'I'he remainder oi .the air enteringvthe inlet 24 flows into. the open lefthand ends of the three identical Venturi tubes 28, where it mixes with an extremely rich mixture of i'uel and air de- -livered to each oi these Venturi tubes by a jet 28. 'I'he iets 28 are connected by piping 30 to a T 32 having a restricted b anch 34 communicating with the bottom of a oat bowl 38 connected by pipe 38 to any suitable source of fuel.A A ram Fig. 3 is a view similar to Fig. 1 but showing 3 a modified form of my invention; and

Fig. 4 is a transverse sectionalview taken on the line 4-4 of Fig. 3.

The heater shown in Figs. 1 and 2 comprises a combustion chamber I0 having an end wall I2 and a cylindrical wall I4. When combustion takes place in the combustion chamber lli, the hot gases resulting from this combustion flow from the open rlghthand end of the combustion chamber around the nose of a muiller I8 and into the annular gas passage I8 formed between the sides oi the muiiler I8 and a cylindrical casing 28.

i of fuel and air is claimed in my-copending ap- As 'the hot gases ow lengthwise of -the annularpassage I8.t hese gases pass between and around Ventilating air tunes 22 which extend lengthwise of the passage I8 in spaced relationship to each other and are arranged circumferentially about this passage. The tubes 22 are preferably of Venturi shape, and the construction and arrangement of these tubes, the mumer I8 and casing 20 constitute a heat exchanger which may be identical with that disclosed and claimed in my copending application, Serial No. 477,908, illed March 4,v

1943. As the gasesilow lengthwise oi the annu- 40 located in the heater inlet 24 is connected by pipe 42.and branch 44. of a T 48 to the-top of the liloat bowl 38. A pipe 48 connects the Ts 22 and 48 .and has a restriction I0 at its point of connection to the T 82.

The Apressure dinerence between the ram 40 and throat of the Venturi tubes and the hydrostatic head oi' the'fuel in the float bowl 38 causes this fuel to flow through restricted branch 34 into T 32 where it mixes with air ilowing into this T through restriction 50. An exceedingly rich mixture of fuel and air is formed in the T 32 and delivered through piping 30 and jets 28 to the throats of the Venturi tubes 28. The mixture delivered by the iets 28 is too rich to burn, Iand a combustible mixture is not formed until the rich mixture delivered by the iets has intermixed with the combustion air which enters the open lefthand ends of the Venturi tubes.

'I'he` structure ior producing the rich mixture plications, Serial No. 456,335 illed August 27, 1942, and Serial No. 460,970 led October 6, 1942. One

advantage of utilizing this structure lies in the fact that a very slight pressure diil'erential between the ram 40 and jets 28suillces to form a rich mixture oi fuel and air and to lift this mixture an appreciable distance where it is inconvenient to have the iloat bowl at substantially the level of the Venturi tube or tubes. In the particular forms of heater shown in this application, it is especially desirable to supply the fue! to the Jets 28 in the form of a rich mixture of l ignlter 58 is disclosed '3 fuel and air than in the form of liquid fuel, since the greater volume of the rich i'uell and air mixture facilitates the division and distribution of the fuel supply among the several Venturi tubes.

Each Venturi tube 28 delivers a mixture of fuel and air-to aninduction tube 52. These induction tubes are identical and eachcomprises a tube of substantially uniform diameter providing a smooth, unobstructed and uninterrupted passage through which Vthe mixture flows to the combustion chamber l at a rate of flow greater pipe 8l which is supplied with a rich mixture of fuel and air byl the means shown in Fig. 1 or by any other suitable means. Each induction tube 80 is a straight section of pipe of uniform diameter and has an inlet end 86 located outside of the combustion chamber 88 and positioned to regcei-ve air from the heater inlet 90.

Each induction tube 80 is inclined relative to the axis of the cylindrical wall 92 of the cornthan the rate of flame propagation, so that comi bustion is confined to the combustion chamber and does not take place in the induction tubes 52. Each induction tube extends in an axial direction through the end wall i2 of the induction@ tchamber land has a curved portion 54 leading to a straight outlet end section 56 which extends along a chord of the cylindrical wall i4. The combustible mixture is discharged from these straight'sections toward and along the circular wall Hand is ignited by an electrical-ignlter 58 to form a ring of flame in the combustion cham- ,bustion ychamber 88 and yextends through the rear wall 94 of this combustion chamber. The inner end of each induction tube 89 terminates in an outlet 96 located in a plane perpendicular to the axis ofthe'combustlon chamber. The outlet ends of the inductionv tubes80 are located a substantial distance from the circular wall 92 of this chamber, and are so positioned that the mixture discharged by these tubes whirls about the axis of the combustion chamber and forms a ring of flame therein when ignited by the electrical lgniter 98.V

In that form of my invention shown in Figs. 3

. and 4, the portions of the induction tubes which ber I8. yThe electrical lgniter is located in a pocket 60 to one side of the combustionchamber' and communicating with this chamber by way of passages 6 2 and 64 in such manner that centrifugal force causes a flow of combustible mixture through the pocket 60 for ignition by the igniter 58. The particular arrangement of the and claimed in my copending application, March 6, 1943. The structure and arrangement of the induction tubes 52 is claimed more broadly in my copending application, Serial No. 477,080 filed February 25, 1943, which application, however, discloses a heater having only a single induction tube. y

Where yonly a single induction tube is utilized, the combustible mixture discharged therefrom must enter the combustion chamber at a high 'rate of flow'in order to form a complete circle of flame about the cylindrical'wall of the combustion chamber. Such an arrangement is eminently satisfactory in` a heater of large capacity, whereas in a heater of smaller capacity and requiring rless combustible mixture, dlfculties have been encountered in providing a sumcient rate of discharge of the combustible mixture from a single induction tube to provide a ring of` ent'arrangement, however, it ls only necessary that the combustible mixture discharged by each induction tube forma relatively short arc of flame in order to provide a complete circle of flame in the combustiony chamber. The outlet end of each induction tube is adjacent the curved portion 54 of the next induction tube in the direction of mixture discharge, so that the burning mixture from one induction tube envelops and heats the outlet end 56 of the next induction tube and assures adequate preheating of the mixture delivered thereby. The length of those parts of the induction tubes which are in the combustion chamber may be varied to give dierent degrees of mixture preheating and ,thus accommodate the heater to light or heavy fuels.

lThe number of induction tubes and the particular arrangement thereof may be varied to secure any desired results. have shown a modified form of my invention utilizing six identical induction tubes 89. A rich mixture of fuel and air is delivered directly to these tubes by the iets 81 connected to a common A In Figs. 3 and 4 I- Serial N0. 478,258 filed extend into the combustion chamber are relatively-short. This has the advantage of permittingfthe use of a combustion chamber which is extremely short but provides relatively little preheating of the combustible mixture by heating of the inwardly extending portions of the induction tubes. An appreciable part of the preheating -ofy the combustion mixture is attained through heating the external portions of the induction tubes by heat transmlttedto these tubes from the end wall 94 of the combustion chamber through metal fillers ,|00 interposed between the wall 94 and the external portions of the induction tubes. Any desired amount of preheating may be obtained by increasing or decreasing the lengths of the external portions of the induction tubes and the extent of the metal fillers connecting these tubes with the combustion chamber wall 94.Y

Except as herein illustrated and described, the embodiment of my invention shown in Figs. 3 and 4 may be identical with that shown in Figs. l and `2. In each of these embodiments, the combustible mixture is supplied to the combustion chamber through induction tubes of uniform diameter and through which the mixture normally flows at a rate greatery than the rate of flame propagation. If the rate of air delivery to the heater inlet should be temporarily reduced, the fiow of combustible mixture in the induction tubes would be correspondingly reduced and some combustion might then take take place in these tubes. Such combustion, however, could not under any 4circumstances extend all the way back to the fuel Jets since the mixture of fuel and air delivered b`y these jets is too rich to be combustible and a combustible mixture is not formed until the rich mixture delivered by these iets has traveled an appreciable distance and has lntermixed with combustion air. As soon as the air flow in the heater inlet has returned to normal, all burning gases are blown out of the induction tubes and into the combustion chamber, and no combustion thereafter continues lin the induction tubes.

While I have illustrated and described only two embodiments of my invention. it is to be understood that my'invention is not limited to the details shown -and'` described but may assume numerous other forms, and that the scope of my invention is denned in the following claims.

, I claim: A l'. A combustion chamber means having. a cylindrical wall, a plurality ofinduction tubes having outlet ends in a plane perpendicular to the axis of said Wall, the axes of said tubes being inclined to said plane, said tubes arranged to discharge combustible mixture tangentially to said wall, means for supplying combustible mixture tosaid induction tubes, means for igniting said mixture, and means providing an igniter pocket communicating at each end with said combustion chamber whereby combustible mixture -is circulated through said pocket and over said igniter by the tangential discharge from said induction tubes.-

2. A heater of the class described, comprising means forming a combustion chamber having a longitudinal axis and a cylindrical wall, a plurallity of-induction tubes having outlet ends equally.

.means cooperating with said combustion chamber to provide an-igniter'pocket communicating 6 cated in said combustion chamber and directed at an acute angleto the cylindrical wall thereof and arranged to discharge a combustible mixture substantially tangentially to said wall and adjacent the end wall of the chamber, means for i8- niting said mixture in the chamber, each of said induction tubes having a portion external to said chamber, heat transmitting means vconnecting said end wall with external portions of said tubes for preheating fuel and air supplied by said tubes to said Jcombustion chamber, and means for supplying fuel and air to said tubes.

6. A heater of the class described, comprising means forming a combustion chamber having an axis, a plurality of induction tubes extending into said chamber and inclined with respect to said axis, said tubes having outlet ends arranged in a circle about said axis, said tubes being arranged at each end with said combustion chamber l whereby a combustible mixture is circulated through said pocket and over said igniter by the tangential discharge froinsaid induction tubes,

means for supplying combustible mixture to said induction tubes, a heat exchanger receiving hot.

products of combustin from said combustion chamber, and means supplying air to said induc` tion tubes and said heat exchanger.

3. A heater of the class described, comprising means forming a combustion chamber having a longitudinal axisand a cylindrical wall, a plurality of straight uniform diameter induction -tubes for supplying combustible mixture to' said chamber arranged in a circle about said axis and .inclined with respect to said axis, each tube being arranged to discharge toward said cylindrical wall at an acute'angle thereto and arranged to cause the mixture to sweep around the wall tangentially thereof, an igniter, means forming an igniterzpocket communicating at each end so that mixture discharged by-said tubes tends to whirl about said axis, means for supplying fuel and air to said tubes, and means for igniting said mixture, together with means providing an igniter pocket which communicates at each end with said combustion chamber whereby combustible mixture is circulated through the pocket and over the igniting means by the whirling discharge from said induction tubes.

' 7. A heater of the class described, comprising means forminga combustion chamber having an axis and including a wall disposed around said axis, a plurality of straight induction tubes of uniform diameter inclined with respect to said axis and arranged to deliver combustible mixture to said combustion chamber in substantially tangential relation to said wall, said tubes having inlet ends outside of said chamber, a jetin each of said tubes, means for supplying a richmixture of fueland air to each of said jets, means for.

` through said pocket and oversaid igniter by the with said combustion chamber whereby con'i.-

bustible mixture is circulated through said pocket and over Asaid igniter by the tangential dis'- charge fromsaid induction tubes, a fuel jet in each of said tubes, and common means for supplying fuel to all of said iets.

4. A heater of the class described, comprising means forming a combustion chamber having a cylindrical wall, several induction tubes'for supplying combustible mixture to said chamber, said induction tubes being straight and in non-parallel relationship to each other, each tube being arranged to ldischarge toward said cylindrical wall at an acute angle thereto land arranged to cause said mixture to sweep around said Wall tangentially thereof, and means for supplying fuel-'and air to said induction tubes, an igniter, and means providing an igniter pocket communicating ateach end with said combustion chamber whereby combustible mixture is circulated through said pocket and over said igniter by the tangential discharge from said induction tubes.

5. A heater of the class described, comprising means forming a combustion chamber of substantially cylindrical form and `having an end wall, a plurality of induction tubes extending through said end wall, each of said' induction tubes having a relatively short outlet portieri losupplying air tc said inlet ends, an igniter, and

means providing an igniter pocket communicating at eachend with said combustion chamber whereby combustible mixture is circulated tangential discharge from said induction tubes.

8. A heater having a heat exchanger and means for supplying air thereto, said heater comprising means forming a combustion chamber having an end wall and a cylindrical side wall,

said cylindrical side wall being attached to said heat exchanger, a plurality of induction tubes passing through said endwali and secured thereto, each of said induction tubes 'having an end vlocated in said combustionchamber and lying in a plane of a chord of said side wall, each of said tubes having a second end in open communication with said air supply means and receiving combustionI air therefrom, a fuel jet in each of I said induction tubes, said fuel jets being external of said combustion chamber and located in said induction tubes adjacent the last-named ends thereof, means attached to said cylindrical .Y

side wall and providing an igniter pocket communicating at each end with the interior of said combustion chamber, an electrical igniter in said pocket, and means for supplying liquid fuel to said jets.

9. A heater of the class described comprising means forming a combustion chamber having a substantially cylindrical wall with an igniter pocket therein communicating with the interior of the combustion chamber, a plurality of tubes for supplying combustible mixture to said chamber, each of said tubes having an outlet end di- .'rected toward said Wall and arranged to discharge combustible mixture which burns as an arc-like part of a complete ring -of iiame in said combustion chamber, each of said tubes-having a portion of substantial length outside said chamber which constitutes an independent carburetor and has an inlet end'remote from' the combustion chamber for receiving air from a source common to all said tubes, a jet in each tube adjacent said inlet end for delivering fuel thereto and so arranged that a combustible mixture is created in each tube, and means for supplying liquid fuel to said jets.

10. A heater of the class described, comprising means forming a combustion chamber having an end wall, a plurality of induction tubes extending through said end wall for supplying combustible mixture to said combustion chamber, each of said tubes having an outlet rend within the chamber constructed to discharge said mixture toward another of said tubes to pre-heat the latter, each tube having a portion of substantial length outside said end wall of the combustion chamber with an inlet end remote therefrom, means for supplying the inlet ends of said tubes with a combustible mixture of liquid fuel and air, and means in the chamber for igniting said mixture.

11. A heater of the class described, comprising means forming a combustion chamber having a cylindrical wall and an end wall, an induction tube of substantially uniform diameterextending through said end wall in a direction axial with respect to said cylindrical Wall, said induction tube having a discharge end portion extending along a chord of said cylindrical wall and located closely adjacent this wall, a pocket opening into said wall with igniting means in said pocket. and means for supplying 'a combustible mixture of liquid fuel and air to said induction tube at a substantial distance from said combustion chamber.

12. A combustion chamber means having a cylindrical wall and an end wall, a plurality of induction tubes of substantial length extending through said end wall for supplying combustible mixture to said chamber, each of said tubes having an outlet end arranged to discharge combustible mixture toward said cylindrical wall and toward the outlet end of another tube, the inlet end of each tube remote from said combustion chamber being open to an air supply', and means for supplying a rich mixture of liquid fuel and 25 air to said inlet ends of said tubes for addition to air entering said tubes from said supply.

HENRY J. DE N. McCOLLUM. 

